Greetings fellow TDIers, New to the forum today. And a bit green to mechanics having only 37 years @ it Currently doing my first BRM camshaft (thank God I though to check it before doing the timing belt)! Thought I would let you know on this same vehicle several months ago I was plagued by a very illusive P0101 MAF code setting but was able to solve the issue quite easily in the end by cleaning it with 99% rubbing alcohol at an actual cost of $2 and 10 minutes time. Unfortunatley I had gone through 3 new MAF sensors before I cleaned the old one Part of the problem was application cross reference (even Bosch) using the stamped number. Note to self - don't use AM parts. The car would sometimes go several miles before setting P0101, ocaisionaly it would hic-cup or burp as boost started under light load (often the 2nd occurance would trigger the code). I have had a great deal of success cleaning the hot wire of many brands of MAF sensors gently using an alcohol soaked Q-Tip but this was the first one I cleaned where the hot wire is not exposed. To clean these MAFs... Remove the sensor from the housing using your tamper proof torx bit and pour about a quarter pint of alcohol into the air inlet of the sensor. Wait about 30 seconds for the alcohol to soften the contamination on the wire and repeat the process. Shake off the alcohol (I do not recommend using compressed air unless from a can - computer keyboard/photography air would work). Shop air is often over 100psi and lethal when used for most cleaning operation of this nature. Once the sensor is completely dry, reinstall, clear your code & try it out. I hope this helps, much more to come. - wherever you go there you are.